. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. LEGUMINOSAE 321 When a bee visits the flower it settles on the alae, and these, being firmly united with the carina as above described, act like the long arm of a lever and cause its depression. The carina and alae return to their original position after the insect visitor has departed. This is partly due to their elasticity, and partly because the upper basal corners of the alae are produced into backwardly and inwardly directed processes, which lie upon th
. Handbook of flower pollination : based upon Hermann Mu?ller's work 'The fertilisation of flowers by insects' . Fertilization of plants. LEGUMINOSAE 321 When a bee visits the flower it settles on the alae, and these, being firmly united with the carina as above described, act like the long arm of a lever and cause its depression. The carina and alae return to their original position after the insect visitor has departed. This is partly due to their elasticity, and partly because the upper basal corners of the alae are produced into backwardly and inwardly directed processes, which lie upon the upper surface of the sexual column. This is also grasped by the two upper basal lobes of the carina, between which only a narrow space is left. And lastly, the broad base of the vexillum curves so far forwards on each side that it completely surrounds the claws of the alae and carina. More than half the length of the extremely short style (only about i^ mm. in length), is beset with hairs from immediately below the terminal stigma downwards. These are longer and closer on the outer than on the inner side. A-. Fig. 105. Vicia Cracca, L. (after Herm. Miiller). (i) Flower seen from the side (x 3I. (2) The same, after removal of calyx and vexillum, seen from above (further enlarged). (3) The same, after the alae also have been removed. (4) Left ala from the inside. (5) Style (still more enlarf^ed). a, anterior alar process; a', corresponding carinal pit; b, posterior alar process; l/, corresponding carinal depression : c, backwardly and inwardly directed alar process ; </, alar claws ; e, carinal claws ; y, dilatation of the carina containing pollen ; ^, upper basal lobes of the carina; A, nectar; 0, opening through which the style passes out; p, styiar brush ; si, stigma. The flowers have barely reached half their full size, when the anthers, which closely surround the styiar brush, dehisce and shed their pollen among the hairs of the brush, the stigma being also covered with
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